Several remarkable scientific discoveries have recently captured global attention. Adding to this array of staggering revelations is the recent buzz on social media surrounding a massive ocean concealed beneath the Earth’s crust. This subterranean water reservoir, stored approximately 700 kilometers below the Earth’s surface within a rock called ringwoodite, boasts a volume three times that of all the planet’s surface oceans combined.
Detailed findings of this discovery were presented in a 2014 scientific paper titled ‘Dehydration melting at the top of the lower mantle’, which also elucidated the unique properties of ringwoodite. Geophysicist Steve Jacobsen, a prominent member of the discovery team, described ringwoodite as akin to a sponge, capable of absorbing water due to its special crystal structure.
Jacobsen remarked, “I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”
This groundbreaking revelation stemmed from researchers’ study of earthquakes, during which they observed seismic shockwaves beneath the Earth’s surface using seismometers.
Elaborating on their findings, the scientists stated, “The high water storage capacity of minerals in Earth’s mantle transition zone (410- to 660-kilometer depth) implies the possibility of a deep H2O reservoir, which could cause dehydration melting of vertically flowing mantle. We examined the effects of downwelling from the transition zone into the lower mantle with high-pressure laboratory experiments, numerical modeling, and seismic P-to-S conversions.”
Additionally, they discovered intergranular melt in the transition zone, suggesting hydration of a significant portion of the transition zone and indicating that dehydration melting might play a role in trapping water in this zone.
Armed with this groundbreaking revelation, researchers aim to gather additional seismic data globally to confirm the prevalence of mantle melting. Their findings hold the potential to revolutionize our understanding of Earth’s water cycle, offering fresh insights into one of the planet’s fundamental processes.
